# US 11,440,471 B2 · Automated warning system to detect a front vehicle slips backwards > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,471 B2 - Document ID: US11440471B2 - Status: Granted - Kind: B2 - Application number: 16/360,986 - Filed: 2019-03-21 - Published: 2020-09-24 - Granted: 2022-09-13 - Earliest claimed: 2019-03-21 - Assignees: Baidu USA LLC - Applicants: Baidu USA LLC - Inventors: Fan Zhu - Web page: https://patentgrep.com/patent/US11440471B2 ## CPC - B60T 17/22: Devices for monitoring or checking brake systems; Signal devices - B60Q 1/46: for giving flashing caution signals during drive, other than signalling change of direction, e.g. flashing the headlights {or hazard lights} - B60Q 1/525: {automatically indicating risk of collision between vehicles in traffic or with pedestrians, e.g. after risk assessment using the vehicle sensor data} - B60Q 5/006: {indicating risk of collision between vehicles or with pedestrians} - B60Q 9/00: Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00 {, e.g. haptic signalling} - B60Q 9/008: {for anti-collision purposes} - B60T 7/22: initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle {, or by means of contactless obstacle detectors mounted on the vehicle} - B60W 30/09: Taking automatic action to avoid collision, e.g. braking and steering - B60W 50/14: Means for informing the driver, warning the driver or prompting a driver intervention - G08G 1/166: {for active traffic, e.g. moving vehicles, pedestrians, bikes} - B60T 2201/02: Active or adaptive cruise control system; Distance control - B60T 2210/20: Road shapes - B60T 2210/32: Vehicle surroundings - B60T 2230/08: Driving in reverse - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES - B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - G08G: TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic B61L; arrangement of road signs or traffic signals E01F9/00; radar or analogous systems, sonar systems, lidar systems specially adapted for traffic control G01S13/91, G01S15/88, G01S17/88; {radar or analogous systems, sonar systems, lidar systems specially adapted for anti-collision purposes G01S13/93, G01S15/93, G01S17/93}) ## Abstract In one embodiment, a system perceives an environment surrounding an ADV including a vehicle in front of the ADV. The system determines whether the vehicle in front is slipping backwards based on the perception. The system determines whether the vehicle in front is situated on a road with a slope based on map information. The system determines whether a tail light or a brake light of the vehicle in front is turned on based on the perception. If it is determined that the vehicle in front is situated on a sloped road, is slipping backwards, and the tail light or the brake light is not turned on, the system calculates a time to impact or a distance to impact based on the distance and speed of the vehicle in front. ## Claims ### Claim 1 A computer-implemented method for operating an autonomous driving vehicle (ADV), the method comprising: perceiving a driving environment surrounding the ADV based on sensor data obtained from a plurality of sensors, including identifying a vehicle in front of the ADV; determining whether the vehicle in front is moving backwardly based on the perception; determining whether a tail light or a brake light of the vehicle in front is turned on based on the perception; and in response to determining that the vehicle is moving backwardly and the tail light or the brake light of the vehicle is not turned on, generating a warning signal to warn a driver of the vehicle in front of the ADV. ### Claim 2 (depends on 1) The method of claim 1, wherein determining whether the vehicle in the front of the ADV is moving backwardly comprises: determining a distance to the vehicle in front at two different points in time; and determining whether the distance to the vehicle in front is decreasing for the two different points in time. ### Claim 3 (depends on 1) The method of claim 1, further comprising determining whether the vehicle in front is situated on a road with a slope based on map information, wherein the warning signal is generated in response to determining that the vehicle is on a sloped road. ### Claim 4 (depends on 1) The method of claim 1, further comprising: calculating a time to impact based on a distance and speed of the vehicle in front; and determining whether the time to impact is less than a predetermined time threshold, wherein the warning signal is generated if the impact time is less than the predetermined time threshold. ### Claim 5 (depends on 1) The method of claim 1, wherein the warning signal includes a short horn sound signal, a continuous horn sound signal, or a flash of a headlamp of the ADV to warn passengers of the vehicle in front of the ADV. ### Claim 6 (depends on 5) The method of claim 5, wherein the continuous horn sound signal is increasing in volume as a distance to impact decreases. ### Claim 7 (depends on 1) The method of claim 1, wherein the warning signal includes a visual and/or audio cue, or a shake of a steering wheel of the ADV to warn passengers of the ADV. ### Claim 8 (depends on 1) The method of claim 1, further comprising: determining whether it is safe to release a brake of the ADV; and releasing the brake of the ADV prior to impact, if it is determined to be safe to release the brake of the ADV. ### Claim 9 A non-transitory machine-readable medium having instructions stored therein, which when executed by a processor, cause the processor to perform operations, the operations comprising: perceiving a driving environment surrounding an ADV based on sensor data obtained from a plurality of sensors, including identifying a vehicle in front of the ADV; determining whether the vehicle in front is moving backwardly based on the perception; determining whether a tail light or a brake light of the vehicle in front is turned on based on the perception; and in response to determining that the vehicle is moving backwardly and the tail light or the brake light of the vehicle is not turned on, generating a warning signal to warn a driver of the vehicle in front of the ADV. ### Claim 10 (depends on 9) The machine-readable medium of claim 9, wherein determining whether the vehicle in the front of the ADV is moving backwardly comprises: determining a distance to the vehicle in front at two different points in time; and determining whether the distance to the vehicle in front is decreasing for the two different points in time. ### Claim 11 (depends on 9) The machine-readable medium of claim 9, wherein the operations further comprise determining whether the vehicle in front is situated on a road with a slope based on map information, wherein the warning signal is generated in response to determining that the vehicle is on a sloped road. ### Claim 12 (depends on 9) The machine-readable medium of claim 9, wherein the operations further comprise: calculating a time to impact based on a distance and speed of the vehicle in front; and determining whether the time to impact is less than a predetermined time threshold, wherein the warning signal is generated if the impact time is less than the predetermined time threshold. ### Claim 13 (depends on 9) The machine-readable medium of claim 9, wherein the warning signal includes a short horn sound signal, a continuous horn sound signal, or a flash of a headlamp of the ADV to warn passengers of the vehicle in front of the ADV. ### Claim 14 (depends on 13) The machine-readable medium of claim 13, wherein the continuous horn sound signal is increasing in volume as a distance to impact decreases. ### Claim 15 (depends on 9) The machine-readable medium of claim 9, wherein the warning signal includes a visual and/or audio cue, or a shake of a steering wheel of the ADV to warn passengers of the ADV. ### Claim 16 (depends on 9) The machine-readable medium of claim 9, wherein the operations further comprise: determining whether it is safe to release a brake of the ADV; and releasing the brake of the ADV prior to impact, if it is determined to be safe to release the brake of the ADV. ### Claim 17 A data processing system, comprising: a processor; and a memory coupled to the processor to store instructions, which when executed by the processor, cause the processor to perform operations, the operations including perceiving a driving environment surrounding an ADV based on sensor data obtained from a plurality of sensors, including identifying a vehicle in front of the ADV; determining whether the vehicle in front is moving backwardly based on the perception; determining whether a tail light or a brake light of the vehicle in front is turned on based on the perception; and in response to determining that the vehicle is moving backwardly and the tail light or the brake light of the vehicle is not turned on, generating a warning signal to warn a driver of the vehicle in front of the ADV. ### Claim 18 (depends on 17) The system of claim 17, wherein determining whether the vehicle in the front of the ADV is moving backwardly comprises: determining a distance to the vehicle in front at two different points in time; and determining whether the distance to the vehicle in front is decreasing for the two different points in time. ### Claim 19 (depends on 17) The system of claim 17, wherein the operations further comprise determining whether the vehicle in front is situated on a road with a slope based on map information, wherein the warning signal is generated in response to determining that the vehicle is on a sloped road. ### Claim 20 (depends on 17) The system of claim 17, wherein the operations further comprise: calculating a time to impact based on a distance and speed of the vehicle in front; and determining whether the time to impact is less than a predetermined time threshold, wherein the warning signal is generated if the impact time is less than the predetermined time threshold.